There are various different types of photovoltaics. They are fairly similar and all serve the same purpose. Most solar companies will have a pre determined brand of panel they use.
Being cut from a single silicon crystal, these solar panels are extremely thin. Due to this they appear smooth, with a sleek texture upon their exterior. The panel's slice will also seem fairly thick as well because of the way that they have been cut. These are usually the most efficient type of solar panel available out there. This also means they are the most expensive to manufacture, so price will be an issue that you will need to consider. Also, due to their rigidity they typically need to be secured within a frame to properly protect them.
These are cut from a far larger block of silicon than the others, giving them far more crystal density to their structure. Although they appear similar to the Monocrystalline with their thickness, their surface has a speckled reflective appearance. Although these are less efficient than the previous one, they are far less expensive because of it. They also need to be installed within a rigid frame as well.
In order to create these, a thin film of silicon that's amorphous is placed over a number of different surfaces. This differs in that being amorphous it's non-crystalline as with the other materials previously. Because of this it is fairly flexible in its nature and composition, with it being produced upon a flexible surface. The main factor to take into account with these particular types of solar panel is the way in which they work to stabilize over a period of time. Over this time period, their power output is reduced. This usually lasts for a few months before stabilizing to a more manageable level. You should then be able to determine what sort of output you can be expecting from them in the long run.
This is typically determined by what sort of budget you are going to be working with. Space is also a factor as this can help define what sort of material you are looking at and how much room it will be taking up. Either way, you still want to make sure that they are effective whatever price you are hoping to pay for them, as this is most important for the long-term.